Radical cystectomy, which is performed to treat muscle-invasive bladder tumors, is among the most difficult urological surgical procedures and puts patients at risk of intraoperative blood loss and transfusion. Fluid management via stroke volume variation (SVV) is associated with reduced intraoperative blood loss. Therefore, we evaluated the efficacy and safety of SVV-guided fluid therapy for reducing blood loss and transfusion requirements in patients undergoing radical cystectomy.This study included 48 patients who underwent radical cystectomy, and these patients were randomly allocated to the control group and maintained at <10% SVV (n = 24) or allocated to the trial group and maintained at 10% to 20% SVV (n = 24). The primary endpoints were comparisons of the amounts of intraoperative blood loss and transfused red blood cells (RBCs) between the control and trial groups during radical cystectomy. Intraoperative blood loss was evaluated through the estimated blood loss and estimated red cell mass loss. The secondary endpoints were comparisons of the postoperative outcomes between groups.A total of 46 patients were included in the final analysis: 23 patients in the control group and 23 patients in the trial group. The SVV values in the trial group were significantly higher than in the control group. Estimated blood loss, estimated red cell mass loss, and RBC transfusion requirements in the trial group were significantly lower than in the control group (734.3 ± 321.5 mL vs 1096.5 ± 623.9 mL, P = 0.019; 274.1 ± 207.8 mL vs 553.1 ± 298.7 mL, P <0.001; 0.5 ± 0.8 units vs 1.9 ± 2.2 units, P = 0.005). There were no significant differences in postoperative outcomes between the two groups.SVV-guided fluid therapy (SVV maintained at 10%-20%) can reduce blood loss and transfusion requirements in patients undergoing radical cystectomy without resulting in adverse outcomes. These findings provide useful information for optimal fluid management during radical cystectomy.